Stalled fermentation

[crimsondrac]

Hi Guys,

Got a problem. The coffee mead I was working on seems to have stalled at about 4% abv. I used K1V which is supposed to be pretty hardy and it bubbled away like crazy for 2 weeks. Not sure what the issue is. Could it be the pH? I do not have any test stips on hand, though I have some on order. Fermentation was going great for a while. SHould I just try to add some energizer and see what happens? What do you recommend? I have come Go Ferm on hand but am out of FermaidK. Any suggestions?

 

[Medsen Fey]

Please provide the complete recipe and process you've used so far - that will help folks give you a better answer.

 

[crimsondrac]

There is a post over in the Brewlog forum, but you are correct, posting it here would indeed be more efficient.

Ingredients:
1 Gallon bottled water
3 Lbs store bought honey
8 Heaping Tablespoons Med. Roast ground coffee (Folgers in my case)
8 - 10 raisins
1 Packet Lalvin K1V-1116 yeast

Starting Gravity: 1.13

Day before making must, I cold brewed 1 gallon of coffee using the 8 table spoons of coffee in a 1 gallon jar. Just put the coffee in the jar, add the water, put on the lid and let sit for 24 hours. This still brews the coffee but does not release the oils and acids that cause much of the bitterness and burnt taste of coffee. After the 24 hours, I filtered it through some cheese cloth lined in a sieve. Collandar would work fine too.

Rehydrated the K1V per the instruction on the packet. Approx. 2 oz of warm water for 15 minutes.

I split the coffee 50-50 into two seperate containers. This would allow me to add the honey then fill the 1 gallon jug to where I want without over filling. So, in one container, add the 3 Lbs of honey and stir vigorously to aerate and dissolve honey in coffee. Added small handful of raisins for a little extra yeast food. Poured remaining coffee into must leaving enough room to prevent a blow out. Pitched the yeast into the must and stirred again.

At this point in time, I put the lid on, added the airlock and stuck it in a cool dark place. The must is black as coffee and smells just like it should, coffee and honey. I have a feeling this will be a black wine. It may lighten up from the fermentation process but it does not look like it will get much lighter, if any.

It started a bit slow, but by the next morning, the airlock was bubbling away. After about 48 hours, I was getting about one bubble every 10-12 seconds from the airlock. I stirred it once the next day and once more the day after. Each time, I got lots of bubbles showing me the yeasties were happy.

 

[AToE]

What's the SG now? (How long since pitch too?)

 

[crimsondrac]

Sorry, thought I had copied that over. I put everything together on 8/7/2010. The current SG is not much lower then the OG of 1.13. I checked it last night with a Vinometer and it came out to approx 4% ABV. The hydrometer reading was around 1.10-1.11

 

[AToE]

Holy smokes did that ever stall... what temperature is it at roughly, and do you have any way to measure PH?

 

[Medsen Fey]

Checking the pH would be a good idea, it is below 3.2, that may be part of the problem.
Have you aerated since pitching? If not, you probably want to do so.
I'm not sure how much YAN you get from coffee. If you have some Fermaid K or other yeast energizer, I'd try adding some.
If it is below 70F, letting it warm up to 70-75 may help get it going.
The coffee you used contains no preservatives, right?

 

[crimsondrac]

Well, I did aerate for about a week after pitching, but I remember reading somewhere, continuing to do so after a period of time oxidizes it rather then helps it so I stopped after about a week.

I am currently out of pH test strips. Have some on order, but probably won't get in till next week. There is one LHBS that I can find but it is all the way on the other side of town. And when you are talking Houston, the other side of town is a journey.

Can I use GoFerm as the energizer? It is listed as a nutrient so I do not know if it will do the same thing.

I keep the A/C in my house between 71-73 so the jug should stay about the same temp, though, I do keep a t-shirt over it to help block out extra light.

Yes, I am sure the coffee does not have any preservatives. It bubbled very nicely for about 2 weeks. That is one of the reasons I am surprised the SG is still so high. It seemed like it was fermenting like mad for a while there. DO not think it would have even started up if there was preservatives in the coffee.

Maybe I will try to hit up the LHBS this weekend to get the test strips. What pH should I be shooting for? What would help raise it or lower it? I am almost positive that is the cause as coffee tends to have high acidity anyways, though I thought I could get around that by cold brewing it. I am thinking pH may be to High.

 

[wayneb]

Actually, your pH might be too low. Although it is confusing at first, low pH means higher acidity. Higher pH is lower acidity, where pH 7.0 is considered "neutral."

For best results most yeasts like the pH of their must to be above around 3.2, and 3.4 to 3.8 is what I consider to be the "ideal" range for a must. Anything higher than pH 4.0 and you can begin to support the growth of all sorts of spoilage organisms. So when you pick up your pH strips, also pick up a chemical (such as potassium carbonate or potassium bicarbonate) that will raise the pH. You can also use calcium carbonate, but it takes longer to react with the acids in the must, so determining the exact right dosage is a little more difficult when you use the calcium compound.